1. Field of the Present Invention
The present invention relates to a centrifugal fan and, more particularly, to a centrifugal fan that discharges air outward from an outlet port formed between an upper casing and a lower casing with rotation of an impeller.
2. Description of the Related Art
A centrifugal fan is widely used for cooling, ventilation, air conditioning, and the like in a variety of equipment such as household electrical appliances, office automation equipment, and industrial equipment, or for a fan installed in vehicles.
JP-A-2014-015849 discloses a configuration of a centrifugal fan in which an impeller is accommodated between an upper casing and a lower casing. Such a centrifugal fan is configured to discharge air suctioned from an inlet port outward from an outlet port formed between the upper casing and the lower casing with rotation of the impeller. The outlet port of air is formed in four side faces of a casing having a rectangular parallelepiped shape.
In a centrifugal fan having the structure described in JP-2014-015849, the impeller is located immediately behind the outlet port. Accordingly, a wide range of the outlet port of the centrifugal fan may be exposed outside when viewed from the outside depending on the how the centrifugal fan is attached or installed in an equipment. In the state in which a wide range of the outlet port is exposed in this way, foreign object such as another member or a user's finger approaches the centrifugal fan, there is a possibility that the foreign object might come into contact with the impeller. When another member or the like comes into contact with the impeller, the impeller may not keep rotating smoothly.